The Early Protective Effect of Hydroxychloroquine on the Risk of Cumulative Damage in Patients with Systemic Lupus Erythematosus

Objective. To assess whether hydroxychloroquine (HCQ) prevents early damage in patients with systemic lupus erythematosus (SLE). Methods. We updated an existing systematic review of literature on clinical effects of HCQ in patients with SLE. We conducted a nested case-control study embedded in an inception cohort of patients with SLE. Systemic Lupus International Collaborating Clinics Damage Index (SDI) at 3 years was considered as our primary outcome. Patients with SDI > 0 at 3 years were considered cases and patients with SDI = 0 were controls. Cases and controls were first compared by univariate analysis. Then conditional logistic regression models adjusting for potential confounders were done to study the effect of HCQ on damage accrual. Results. Included in the analysis were 481 patients who had 3 or more years of followup. Out of this cohort, we could match 151 cases with 151 controls. Univariate analysis identified age, the use of any immunosuppressive drugs, HCQ, and cumulative dose of steroids as significant covariates associated with damage accrual. In multivariate analysis, the use of HCQ remained significantly associated with less damage (OR 0.34, 95% CI 0.132-0.867), while age (OR 1.05, 95% CI 1.027-1.078) and a variable combining SLE activity and steroid dose (OR 1.73, 95% CI 1.306-2.295) were associated with damage at 3 years. Conclusion. We demonstrated that HCQ use was associated with less damage at 3 years after diagnosis of SLE when attention was given and adjustment done for disease activity and steroid dose, duration of disease, and calendar year of diagnosis.